The teddy boys used bike chains and straight razors.
This despite there being a lot of WW@ surplus bayonets and revolvers knocking and available.
But the teds knew that was serious jail time/the rope if they got caught.
Laws on 'offensive weapons' - chains and razors - were applied vigorously.
There are plenty of laws re knives and swords, yet they aren't implemented harshly these days.
And by rather fortuitous coincidence, a video was published today by a well known expert on British military sabres which covers some of the development of the 1796 LC sabre. He also happens to be an antique sword dealer and runs one of the UK's top historical fencing clubs.
At that price it may fall apart if you swing it around. The attachment of the blade to the hilt in particular may be very weak. Many of the lower price ones are made for hanging on the wall as decoration and are weakly made of poor quality metal.
There is by the way zero evidence for the existence of special straight "ninja" swords in historic times. They are an invention of the modern movie industry (along with black "ninja" costumes) so the audience can more easily tell the "baddies" from the "goodies". However, they appeal to certain people who want one because it was in a movie they liked, much like other movie "collectibles". They are not necessarily intended for actually hitting anything with.
While the nnjato is a myth (it's a blunt fishmongers tuna knife, used in films for the reasons you state and because it was cheaper), I have seen in the Leeds Royal Armouries a period "straight" Samurai sword blade with provenance and a contemporary woodcut showing one been worn. They were a fashion at the time English, Dutch and Portuguese traders were in japan and very loosely styled after the European rapier blade.The woodcut also shows young samurai with their hakama bloused in imitation of the baggy trousers that European traders and sailors were wearing.
In the same Museum in Leeds there is a naginata styled as a halberd.
The blade while straight did not have a straight cutting edge but had a slight belly before the kissaki (stabby bit) though you could have used the mune (back of blade) as a ruler, so it should still be able to cut on the draw.
Masonic swords tend to be straight edged so thats the daft sword law delt with. It would be fine to transport in public, being used for ceremonial purposes it would come under historical/religious. Besides, can you see plod lifting someone from the local lodge for going about their lawful business?